Preparation and Characterization of Nanometer Sized TiO2 Thin Film Sintered at Low Temperature

近二十几年来，纳米二氧化钛(TiO2)在光催化、新型太阳能电池等领域的应用越来越显示出诱人的前景，受到越来越多的关注。溶胶－凝胶法(sol-gel)因所需设备简单，制得的薄膜纯度高，晶粒平均粒径小且分布窄、活性高等优点，成为制备TiO2薄膜常用的方法之一。Sol-gel法制得的纳米TiO2薄膜，一般经过450～550℃热处理，且在晶型、薄膜厚度、均匀度等方面均难以控制(本文称之为传统sol-gel法)，使TiO2薄膜的应用受到一定限制，进一步的影响产业化发展。近几年来，低温制备TiO2薄膜的研究正在兴起。目前在低温下获得透明的、具有锐钛矿晶型的TiO2薄膜主要方法是用sol-gel法直接制备具...In recent twenty years, nanometer sized TiO2 is a promising semiconductor photocatalysis that has a variety of application in field of photocatalysis and dye-sensitized solar cell. The method of sol-gel is often used for preparation of nanometer sized TiO2 thin film, because it needs simple equipment and the grain size of TiO2 thin film prepared by this method has the advantage of pure crystal, sm...学位：理学硕士院系专业：化学化工学院化学系_无机化学学号：20042502

Hydrophilicity of TiO_2 Thin Films Codoped with Iron and Nitrogen

[中文文摘]采用溶胶-凝胶法制备了铁掺杂TiO2(Fe-TiO2)薄膜,将Fe-TiO2薄膜放置氨气气氛中高温处理,形成铁、氮共掺杂TiO2(Fe/N-TiO2)薄膜.通过XRD、XPS、SEM、UV-Vis法进行吸收光谱分析及薄膜表面亲水接触角分析,研究了铁、氮掺杂浓度,热处理温度,膜厚等因素对薄膜亲水性能的影响.结果表明,Fe/N-TiO2(0.5%Fe,摩尔百分数)显示出更佳的亲水性能,在可见光下优势尤为明显.铁掺杂主要作用是降低电子和空(的复合几率,氮掺杂可以增强TiO2薄膜在可见光区的吸收,两种效应相互结合,共同提高了薄膜在可见光下的亲水性能.[英文文摘]TiO2 doped with iron(Fe-TiO2)thin films were synthesized using sol-gel method.TiO2 codoped with iron and nitrogen(Fe/N-TiO2)thin films were prepared by calcining Fe-TiO2 thin films in ammonia atmosphere.The influence of iron and nitrogen doping concentration,heat-treatment temperature and film thickness on the hydrophilicity of the films were studied by XRD,XPS,SEM,UV-Vis spectra and measured water contact angle.The results indicated that Fe/N-TiO2(0.5%Fe,molar percent)films were optimum in hydrophilicity,especially under visible-light irradiation. Doping iron mostly reduced the recombination of electrons and holes, and doping nitrogen in TiO2 enhances photoresponse in visible-light region. The hydrophilicity benefited from both effects.国家自然科学基金(50472057

Preparation and Photocatalytic Activity of TiO_2 Powder Codoped with Iron and Nitrogen

Using TiCl4 as the titanium source, nanoparticles of TiO2 doped with nitrogen(N-TiO2) were synthesized by triethylamine. TiO2 powder codoped with iron and nitrogen(Fe/N-TiO2) were prepared by adsorption-deposition of Fe3+ on N-TiO2 and calcining at 400 ℃ for 2 h. From the XPS results for N1s binding energy at 399.6 eV and 396.6 eV, it is proposed that the partial N atoms as substitution atoms replace for O atoms in TiO2 lattice. The onset of the absorption spectrum of Fe/N-TiO2 has a 45 nm red-shift compared with that of TiO2. The results of photocatalytic degradation of methylene blue solution indicate that Fe/N-TiO2 (0.45% Fe3+) has a higher activity.Its photocatalytic activity is about 2 times as high as that of pure TiO2 under UV-light, and 3 times under sunlight. Doping of nitrogen in TiO2 enhances photoresponse in visible light region and doping of Fe3+ reduces the recombination of electrons and holes. Both of the above effects are beneficial for improving the performances of Fe/N-TiO2 photocatalyst.国家自然科学基金(No.50472057

Preparation and photocatalytic activity of TiO2 powder codoped with iron and nitrogen

Using TiCl4 as the titanium source, nanoparticles of TiO2 doped with nitrogen (N-TiO2) were synthesized by triethylamine. TiO2 powder codoped with iron and nitrogen (Fe/N-TiO2) were prepared by adsorption-deposition of Fe3+ on N-TiO2 and calcining at 400 degrees C for 2 h. From the XPS results for N1s binding energy at 399.6 eV and 396.6 eV, it is proposed that the partial N atoms as substitution atoms replace for O atoms in TiO2 lattice. The onset of the absorption spectrum of Fe/N-TiO2 has a 45 nm red-shift compared with that of TiO2. The results of photocatalytic degradation of methylene blue solution indicate that Fe/N-TiO2 (0.45% Fe3+) has a higher activity. Its photocatalytic activity is about 2 times as high as that of pure TiO2 under UV-light, and 3 times under sunlight. Doping of nitrogen in TiO2 enhances photoresponse in visible light region and doping of Fe3+ reduces the recombination of electrons and holes. Both of the above effects are beneficial for improving the performances of Fe/N-TiO2 photocatalyst

Hydrophilicity of TiO2 thin films codoped with iron and nitrogen

TiO2 doped with iron (Fe-TiO2) thin films were synthesized using sol-gel method. TiO2 codoped with iron and nitrogen (Fe/N-TiO2) thin films were prepared by calcining Fe-TiO2 thin films in ammonia atmosphere. The influence of iron and nitrogen doping concentration, heat-treatment temperature and film thickness on the hydrophilicity of the films were studied by XRD, XPS, SEM, UV-Vis spectra and measured water contact angle. The results indicated that Fe/N-TiO2 (0.5%Fe, molar percent) films were optimum in hydrophilicity, especially under visible-light irradiation. Doping iron mostly reduced the recombination of electrons and holes, and doping nitrogen in TiO2 enhances photoresponse in visible-light region. The hydrophilicity benefited from both effects

Hippo Signaling Suppresses Cell Ploidy and Tumorigenesis through Skp2

大多数真核生物的体细胞是二倍体，即仅含有两组染色体，分别遗传自父本和母本。而一些特定组织如心脏、肝脏等就含有多倍体细胞，特别是肝脏组织含有较高比例的四、八倍体等多倍体细胞。肝脏是人体的重要解毒器官，同时酒精、肝炎病毒等毒性物质或毒性代谢物容易诱发肝细胞的基因突变，多倍体被认为有利于提供代偿性的正常基因来维持肝脏稳态。然而肝脏受损后，多倍体细胞将会受胁迫进行增殖，再生修复受损的肝组织。因此研究机体调控多倍体细胞产生及多倍体细胞进行细胞分裂的调控机理对于理解肝癌的发病机理和肝癌的治疗至关重要。Hippo信号通路在调节组织成体干细胞的分化和增殖，调控器官再生与尺寸大小中具有重要作用。深入研究发现, Hippo信号通路下游效应分子YAP通过AKT-SKP2信号促进二倍体细胞向多倍体转化及多倍体细胞的生长增殖。本项研究阐明了Hippo缺失及YAP激活促进多倍体细胞产生及增殖作为肝癌发生发展中的一个重要机制，为肝癌诊疗提供了新的策略。 周大旺，博士，厦门大学生命科学学院教授、副院长、国家杰出青年基金获得者。【Abstract】Polyploidy can lead to aneuploidy and tumorigenesis. Here, we report that the Hippo pathway effector Yap promotes the diploid-polyploid conversion and polyploid cell growth through the Akt-Skp2 axis. Yap strongly induces the acetyltransferase p300-mediated acetylation of the E3 ligase Skp2 via Akt signaling. Acetylated Skp2 is exclusively localized to the cytosol, which causes hyper-accumulation of the cyclin-dependent kinase inhibitor p27, leading to mitotic arrest and subsequently cell polyploidy. In addition, the pro-apoptotic factors FoxO1/3 are overly degraded by acetylated Skp2, resulting in polyploid cell division, genomic instability, and oncogenesis. importantly, the depletion or inactivation of Akt or Skp2 abrogated Hippo signal deficiency-induced liver tumorigenesis, indicating their epistatic interaction. Thus, we conclude that Hippo-Yap signaling suppresses cell polyploidy and oncogenesis through Skp2.该研究工作获得了国家自然科学基金委、国家重点基础研究发展计划(973)项目、青年千人计划和中央高校基本科研基金的资助。 The Yap (S127A) transgenic mice were kindly provided by Dr. Fernando Camargo from Harvard Medical School, Boston, MA. D.Z. and L.C. were supported by the National Natural Science Foundation of China (31625010,U1505224, and J1310027 to D.Z.; 81422018, U1405225, and 81372617 to L.C.; 81472229 to L.H.), the National Basic Research Program (973) of China (2015CB910502 to L.C.), the Fundamental Research Funds for the Central Universities of China-Xiamen University (20720140551 to L.C. and 2013121034 and 20720140537 to D.Z.)

碳酸氢钠浸出硼精矿制备硼砂的新工艺

针对碳碱法处理硼精矿生产硼砂过程中存在的反应时间长、操作不安全、能耗高、资源利用率低等缺点，本论文结合侯氏制碱法，提出用侯氏制碱法的中间产物NaHCO3 直接处理硼精矿熟料制取硼砂的新工艺，为开发加工东北硼铁矿提供了新的工艺思路。本论文对硼精矿熟料在NaHCO3溶液中的溶出过程、NaHCO3-Na2B4O7-H2O理想体系的溶解度和初级成核动力学、硼砂在NaHCO3水溶液体系中的结晶过程进行了研究。系统考察了液固质量比、NaHCO3用量、反应温度、反应时间、搅拌速度等工艺条件对溶出过程的影响。在液固质量比为2.1，NaHCO3用量为理论用量的150%，溶出温度为100℃，溶出时间为60 min，搅拌速度为400 r/min时，硼精矿熟料的碳解率最高，硼的提取率可达92.88%。硼精矿熟料的物相主要为金云母、遂安石、利蛇纹石和橄榄石，硼精矿熟料与NaHCO3溶液反应，最终得到的终硼泥的物相中出现了MgCO3，Na2Mg(CO3)2新物相，遂安石物相消失。考察了各浸出工艺条件对硼精矿熟料中杂质元素浸出率的影响：Ca元素的浸出率在液固比超过1.7:1后增加不明显，Fe元素、Mg元素的浸出率在液固质量比超过2.3:1后几乎不再增加，Al元素、Si元素的浸出率在所考察范围内随着液固比的增加一直增大；碳酸氢钠用量超过理论用量的100%后，Fe元素、Mg元素的浸出率随碳酸氢钠用量增加增大不明显，Al元素、Si元素的浸出率在所考察范围内随着碳酸氢钠用量的增加而增加，碳酸氢钠用量超过理论用量的150%后，Ca元素的浸出率增加不明显；Ca元素的浸出率的最佳浸出温度为100℃，在120℃时，Fe、Mg、Si元素的浸出率最高，Al元素的浸出率在所考察浸出温度范围内随浸出温度升高而增加。Ca、Fe、Mg元素的最佳浸出时间为60 min，Al、Si元素的浸出率在所考察浸出时间范围内随浸出时间增加而增大；Fe、Mg、Si、Al元素的浸出率随着搅拌速度的加快而增大，Ca元素的浸出率随搅拌速度增加变化不大。测定了298 K和308 K时的NaHCO3-Na2B4O7-H2O体系的溶解度等温线，可知可用冷却结晶法将硼砂晶体从NaHCO3溶液中结晶出来。同时测定了NaHCO3-Na2B4O7-H2O体系的结晶成核诱导期，实验结果表明 NaHCO3-Na2B4O7-H2O体系属于易结晶体系。析出硼砂晶体在较高结晶温度下为椭圆状或不规则晶体形成的聚结体；较低温度下，随着过饱和度的增加，析出硼砂晶体由圆片状变为三棱柱状。分析了不同结晶条件下的晶体物相，所得晶体物相均为硼砂。对硼砂在NaHCO3溶液中的结晶过程进行研究，系统考察了结晶时间、结晶温度、溶液过饱和度和搅拌速度等工艺参数对结晶过程的影响。结晶时间增长，对晶体生长有利，所得硼砂晶体粒径增大。在结晶时间小于90 min时，随着结晶时间的增加，硼砂晶体的结晶率增加，结晶时间超过90 min后，硼砂结晶率增加不明显。结晶温度的升高使得小粒径硼砂晶体数增加，对硼砂结晶过程是不利的。溶液的过饱和度越大，所得硼砂晶体的粒径越小，过饱和度比较大的情况下，对硼砂晶体的生长变大是不利的。搅拌速度越大，硼砂晶体粒径越小。;Preparing borax by CO2-soda method has many shortcomings, such as long reaction time, unsafe operation, high energy consumption, low resource utilization rate. In order to solve these problems, a new process which combining with Hou&rsquo;s process for soda production, NaHCO3 as the intermediate product of Hou&rsquo;s process for soda production was used to react with boron concentrate to prepare borax was proposed. It provides a new process for the exploitation and utilization of ludwigite in northeast China. In this paper, the leaching of boron concentrate in NaHCO3 solution, the solubility and primary nucleation dynamics of NaHCO3-Na2B4O7-H2O ideal system and the crystallization process of borax in the NaHCO3 aqueous solution were studied.The effects of liquid-solid mass ratio, NaHCO3 consumption, reaction temperature, reaction time and stirring speed on the leaching process of B was investigated systematically. The results showed that under the optimum conditions of mass ratio of liquid to solid of 2.1:1, sodium bicarbonate consumption of theoretical amount of 150%, leaching temperature of 100℃, leaching time of 1 h, stirring speed of 400 r/min, leaching rate of B reached 92.88%. The major phases in the calcined boron concentrate were suanite, lizardite, phlogopite and olivine. After boron concentrate reacted with the NaHCO3 solution, with the suanite phase disappearing, the major phases in the boron sludge obtained were MgCO3 and Na2Mg(CO3)2.The effects of process conditions on leaching rate of the impurity elements in boron concentrate were investigated. When the mass ratio of liquid to solid was more than 1.7:1, the leaching rate of Ca increased unobviously. The increase of the leaching rate of Fe element and Mg element was not obvious, if the mass ratio of liquid to solid was more than 2.3:1. In the investigation range, the leaching rate of Al element and Si element increased with the increase of the mass ratio of liquid to solid. When the sodium bicarbonate consumption was more than 100% of the theoretical amount, the leaching rate of Fe element and Mg element increased unobviously as the sodium bicarbonate consumption increased. In the investigation range, with the increase of sodium bicarbonate consumption, the leaching rate of Al element and Si element increased. When the sodium bicarbonate consumption was more than 150% of the theoretical amount, the increase of the leaching rate of Ca element was not obvious. The optimum leaching temperature of Ca element was 100℃. The leaching rate of Fe element, Mg element and Si element was highest at the leaching temperature of 120℃. In the investigation range, the leaching rate of Al element increased with leaching temperature increased. The optimum leaching time of Ca element, Fe element and Mg element was 60 min. In the investigation range, the leaching rate of Al element and Si element increased with the increase of leaching time. The leaching rate of Fe element, Mg element, Si element and Al element increased with the increase of stirring speed, and the leaching rate of Ca element changed little with the increase of stirring speed.The solubility isotherm of NaHCO3-Na2B4O7-H2O system at 298 K and 308 K was measured, and it was known that the crystal of borax could be crystallized from the NaHCO3 solution by cooling crystallization method. At the same time, the nucleation induction period of NaHCO3-Na2B4O7-H2O system was measured. The experimental results indicated that NaHCO3-Na2B4O7-H2O system belongs to easy crystal system. At higher crystallization temperature, the borax crystal obtained was aggregate formed by elliptical or irregular crystals. At lower crystallization temperature, the morphology of borax crystal obtained changed from round sheet to triangular prism. The phases of crystals obtained at different crystalline conditions were analyzed. The crystals were all borax.The crystallization process of borax in NaHCO3 solution was studied. The effects of crystallization time, crystallization temperature, solution oversaturation and stirring speed on the crystallization process were investigated systematically. The increase of crystallization time was good for crystal growth, and the partical size of borax crystal obtained increased. When the crystallization time was less than 90 min, the crystallization rate of borax crystal increased with the increase of crystallization time. The increase of crystallization rate of borax crystal was not obvious, when the crystallization time was less than 90 min. The increase of crystallization temperature which was adverse for the crystal process of borax increased the number of small size borax crystals. When the solution saturation was higher ,the particle size of borax crystal obtained was smaller. High solution saturation was not good for the crystal growth. With stirring speed increasing, the particle size of borax crystal obtained became smaller.&nbsp;</p

What Contribute to Success and Failure of Diversified Financial Institutions: A Case Study

1. Introduction / 2. Research Design / 3. Data and Performance Comparison / 4. Case Study : Why There Are Winners and Losers / 5. Findings and Discussion / 6. Conclusio